I've been having fun last couple of days downloading some U.S. water use datasets, importing them in Manifold GIS, making them map ready and then uploading them back on Geocommons. Using the Map Maker I have then presented the results in a couple of maps.
The first shows the total ground water usage by state in millions of gallons per day (colored states) and also ground water use as percent of total water use (graduated dots). Orange blocks as urban centres with population greater than fifty thousand. You can see the east west divide in water use type. The east relies a lot more on surface water. The central and western areas along with Florida in the south east rely on ground water more than the eastern states. The importance of the Ogallala or High Plains Aquifer is clearly seen in the central states as is the importance of the Central Valley Aquifer in California.
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You can drill down and bring out other dimensions of this data. For example in the map below I've plotted one of these dimensions, the ground water usage for irrigation in millions of gallons per day in the High Plains counties. The High Plains Aquifer is outlined.
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This is not a full "cloud GIS" yet in terms of users borrowing or leasing the full range of GIS functionality from a remote computer. I had to follow a hybrid approach as did other data donors in terms of using a personal GIS to process the data to certain specifications before uploading it to this online service. Still such services are gaining importance and functionality and they give users who don't own software an inexpensive tool to actively engage with spatial data.
Not surprising about California. Unfortunately legislation is needed in spades to counter those that seem to enjoy the freedom to dig their children and grandchildrens graves.
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